l4-hackers Digest, Vol 112, Issue 3

[raylei0825ssdut]

I just remove the statement "msr cpsr_c,r7". But It just doesn't Work. And If I change the code to the following:
I set the vcpu_state_t registers  as following :
  vcpu->r()->r[6]=(l4_umword_t)exit_map_addr;
  vcpu->r()->r[4]=(l4_umword_t)(idle_stack+sizeof(idle_stack)-1);  vcpu->r()->ip =(l4_umword_t)super_code_map_addr;  vcpu->r()->r[5] = (l4_umword_t)idle_code_map_addr;  vcpu->r()->sp = (l4_umword_t)0x30000;
and I change the my_super_code :
asm (    ".pushsection .text\n"  ".p2align 12         \t\n"  ".global my_super_code  \t\n"  "my_super_code:   \t\n"
" swi 0       \t\n"
" mov sp, r4   \t\n"" mov lr, r6   \t\n"" mov pc, r5   \t\n"".popsection");
and still, it doesn't work.And The vcpu upcall function 
will be called again and again.

2012-08-03



raylei0825ssdut



发件人：l4-hackers-request
发送时间：2012-08-03 18:00
主题：l4-hackers Digest, Vol 112, Issue 3
收件人："l4-hackers"<l4-hackers at os.inf.tu-dresden.de>
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Today's Topics: 

   1. Re: vcpu example problem (Adam Lackorzynski) 


---------------------------------------------------------------------- 

Message: 1 
Date: Thu, 2 Aug 2012 22:14:21 +0200 
From: Adam Lackorzynski <adam at os.inf.tu-dresden.de> 
To: l4-hackers at os.inf.tu-dresden.de 
Subject: Re: vcpu example problem 
Message-ID: <20120802201421.GA7129 at os.inf.tu-dresden.de> 
Content-Type: text/plain; charset=iso-8859-1 

Hi, 

On Thu Aug 02, 2012 at 11:14:34 +0800, ?????? wrote: 
> Hi, 
>        I  am trying  to modify the vcpu example of l4re-snapshot to 
> switch registers to execute my C function.But It doesn't work. 
>        I have read some papers about l4linux tranplantion.and follow it . 
>        To switch the process, I fill the vcpu_state_t structure with 
> its registers.and call vcpu_resume_commit action.Then Jump to the ASM 
> Code. 
>        But problem arises when I want to jump from asm code to C 
> function. What's the Problem? The Code is as following: 

> #define SVC_MODE    0x00000013 
> #define USR_MODE    0x00000010 

>  
> asm volatile 
> ( 
>   ".pushsection .text\n" 
>   ".p2align 12         \t\n" 
>   ".global my_super_code  \t\n" 
>   "my_super_code:   \t\n" 
> "    msr    cpsr_c, r7\t\n" 
> "    mov    lr, r6   \t\n" 
> "    mov    pc, r5   \t\n" 
> //"       b       my_super_code \t\n" 
> ".popsection" 
> ); 

I think the problem is not the jump but the msr, which you cannot do in 
user-land and which you probably can safely remove. 



Adam 
--  
Adam                 adam at os.inf.tu-dresden.de 
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/ 



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